Hunting for nukesInternational inspectors are finally back in Iraq,
searching for biological, chemical and nuclear weapons. At stake is another
war in the Middle East.

These days, nuclear weapons get less attention than
they did during the long atomic standoff called the Cold War. Yet long
after the "nuclear genie" escaped the bottle, the bomb is spreading faster
than ever. Since the United States invented the atomic ("fission") bomb
in 1945 and then the vastly more powerful hydrogen ("thermonuclear ")
bomb, the Soviet Union, the United Kingdom, France, China, India, Pakistan
and probably Israel have built nuclear weapons.

North Korea, and perhaps Iraq and Iran could be
poised to join the once-select "nuclear club." Despite treaties designed
to halt the spread of nuclear weapons and to wean the nuclear powers from
the bomb, the nuclear arms race continues. Indeed, in the past couple
of years, it seems to have accelerated:

The
Bush Administration has renounced the Anti-Ballistic Missile treaty, and
backed away from the Comprehensive Test Ban Treaty. The Bush administration's
recent Nuclear Posture Review calls for a reliance on nuclear weapons
for decades to come.

This
spring, India and
Pakistan - enemies since they were born in 1947 - went to the brink
of war over the disputed territory of Kashmir. Both nations exploded nuclear
bombs in 1998.

This fall, North Korea revealed that, despite its
assurances, it has material for a few bombs.

The United States is modifying a trusty warhead
for a new mission. The improved B-61 is intended to penetrate deep into
the earth, to knock out underground factories and bunkers. Critics charge
that the "bunker buster" is a retreat from treaty obligations and represents
a trend toward greater reliance on nuclear weapons (see "Nuclear Study..."
in the bibliography).

The Russian arsenal contains about 10,000 warheads,
riding a similar collection of steeds.

That is a lot of nukes - plenty to cook our home
planet. Between rogue nations, technical blunders, political errors, terrorists
and nuclear-armed psychopaths, there's plenty of reason to worry.

The first atomic bomb was exploded in the New Mexico desert in July, 1945.
Physicist Isidor Rabi recalled: "Suddenly, there was an enormous flash
of light, the brightest light I have ever seen or that I think anyone
has ever seen. It blasted; it pounced; it bored its way right thorough
you. It was a vision which was seen with more than the eye. It was seen
to last forever. You would wish it would stop; altogether it lasted about
two seconds.... A new thing had just been born...." From "The Making..."
(see bibliography).National
Atomic Museum.

There is already plenty to worry about, nuclear-wise.
But are the nuclear wizards content with what they've invented? Or
are they trying to build bombs based on new physical principles, which
would represent a new category of threats?

With thermonuclear weapons now able to fit an artillery
shell, many observers dismiss the threat. "It's hard see how any new thing
would come to the level of things we've had for 40 years," says Ray Kidder,
a veteran weapons designer who started working at Lawrence
Livermore National Laboratory in 1956, and eventually directed work
on theoretical aspects of weapons development and high-energy lasers.

"You hate to say the problem has been solved, but
it's been oversolved, from my point of view," Kidder continues. "We have
high-yield weapons that can create fires all over the place, and weapons
that can blow cities down ... that you can put in a small suitcase. All
these talked-about new things, it's not quite clear what improvement they
would be."

Not only would there be little reason to search
for new nuclear principles, Kidder says, but there is little prospect
of success - at least in the near term. The ideas discussed in this article,
he says, "do not present any kind of immediate risk, in terms of being
put into practice in 10 years, if ever."

However, technology has never moved this fast, and
it's impossible to predict 20 or 50 years into the future. "Ten years
is about all you can say," Kidder admits. Kidder, and all responsible
scientists, never say "never."

At any rate, nuclear weapons labs -- both here and,
presumably elsewhere -- have tried to build nuclear devices that might
be smaller, cheaper, or less powerful or radioactive.

The concern about -- and interest in -- new nukes
is driven by one physical fact: The fusion of a single gram of hydrogen
or helium packs more wallop than the largest conventional bomb. Whether,
in the post- 9/11 world, it makes sense to find new ways to ignite fusion
in a super- compact weapon is something we'll leave to your imagination.

Why me worry? We have lived under the shadow of nuclear weapons
for decades. A few new-style bombs, what's the big dif? Here's fuel for
fretting:

Smaller
bombs would blur the line between conventional and nuclear weapons, making
nukes more acceptable.

Low-radioactivity bombs would, well, ditto. "Thermonuclear
weapons are dirty, essentially all of them create a lot of fallout," says
Arjun Makhijani, a physicist who is president of the Institute
for Energy and Environmental Research, "and that has a pretty serious
liability in terms of occupying a country with your soldiers, or irradiating
your own people."

Once invented, technologies spread. It's much harder
to invent, say, a computer than to take one apart and copy ("reverse engineer")
it. But just knowing something is possible creates an incentive to try
to build it.

Politically, the message that the United States
is not content with its overwhelming military superiority may cause other
nations to ramp up their own research. In other words, fourth-generation
research could trigger a new nuclear arms race.

This world leader wants to join the big boys - with his own nuclear toys. Courtesy Gendercide
Watch.

A defining moment What is this 4-gen jargon, you ask? "Fourth-generation
nuclear weapon" essentially refers to any nuclear weapon yet to be invented.
Some 4-gens would simply miniaturize the atomic bomb, but many would create
fusion -- a hydrogen bomb -- without setting it off with an atomic bomb.

All these weapons, we must add, remain to be built.
In other words, you are reading informed speculation about weapons
not yet invented.

Word about new nuclear gadgets leaked in the 1970s,
when the United States deployed the enhanced-radiation ("neutron") bomb.
Derided as the ultimate capitalist weapon (it was more effective against
people than property), the neutron bomb had little military utility, and
was later withdrawn from the arsenal.

More frightening was the X-ray laser, physicist
Edward Teller's conception of a thermonuclear ray gun that supposedly
would destroy hundreds of Soviet warheads. For years, the X-ray laser
was at the heart of Star Wars,
President Ronald Reagan's anti-missile program. Despite the investment
of billions on research and development, the laser fizzled.

Reality check So much for third-generation nukes. What about the
fourth-generation? To some people, they are a hodgepodge of unlikely,
impossible, impractical and unnecessary ideas. Even critics of the nuclear
establishment worry more about today's threats than those that may not
materialize for decades.

While the pace of technological change has never
been faster, the nuke that could ruin your whole day -- today -- was invented
half a century ago.

Nevertheless, 4-gens represent a long-term menace,
if they are possible at all. Inventions get around. Important discoveries
like the jet plane and Jell-O. Trivial ones like movie sequels and prequels.
Malignant ones like bagels with the consistency of Wonder Bread.

And dangerous ones, like nuclear weapons.

If you don't worry about advanced nuclear-weapon
research as long as it's done by the "the good guys," consider this: 67
years after the first atomic bomb was detonated, at least seven countries
have them.

We asked the Department of Energy and some of the
national laboratories about their work on 4-gens, but they, with one limited
exception which we'll describe later, did not answer our phone calls and
e-mails.

Too bad. But then again, in the nuclear business,
the only safe bet is that those who tell don't know, and those
who know don't tell.

If the U.S. Department of Energy were working on
fourth-generation nuclear weapons, we would not expect them to tell us,
especially in the current climate of secrecy. (Websites run by the weapons
labs have lots of dead links to pages apparently withdrawn in the name
of national security.)

What me worry? You might think the end of the Cold War and the rise
of arms-control treaties would have dampened nuclear research. The 1968
Treaty on the Non-Proliferation
Treaty of Nuclear Weapons (NPT), for example, is described by the
United Nations as a "binding commitment in a multilateral treaty to the
goal of disarmament by the nuclear-weapon States."

It ain't necessarily so. The new U.S. Nuclear Posture
Review and the "Science
Based Stockpile Stewardship" program both indicate
a renewed interest on the part of the Bush Administration in modernizing
existing weapons and perhaps inventing new types.

Spending at the U.S. nuclear complex, $5.9 billion
per year, "is well above Cold War average spending," which averaged $4
billion in current dollars, says Christopher Paine of the Natural
Resources Defense Council. "Ten years after the Cold War ended, what
are these people doing?"

And is what they are doing wise? Would inventing
fourth-generation nuclear weapons really make us better off? Or would
we, in 30 or 50 years, be worrying that Pakistan, China, or even al Queda
version 3.0 has weapons invented at a U.S. Department of Energy Lab?

The issue raises a question seldom heard in science:
Is some knowledge too dangerous ? Are some genies best
left in the bottle?

Hans Bethe, a professor emeritus of physics at Cornell
University, who directed theoretical physics at Los Alamos when the atomic
bomb was invented, has urged restraint. In a 1997
letter to Pres. Clinton, he argued: "The United States already possesses
a very wide range of different designs of nuclear weapons and needs no
more. Further, it is our own splendid weapons laboratories that are, by
far and without any question, the most likely to succeed in such nuclear
inventions. Since any new types of weapons would, in time, spread
to others and present a threat to us, it is logical for us not
to pioneer further in this field."

In nuclear weaponry, it's tough to innovate; much
easier to play copycat.